This disclosure relates generally to electric machines. More specifically, this disclosure relates to support and retention of rotor magnets in electric machines.
Rotors of electric machines typically include permanent magnets inserted between pole pieces of the rotor. The magnets, typically rectangular in cross-section, are placed into aluminum packets and inserted into rectangular slots between the pole pieces. Because of the rectangular cross-sections of the magnets and the slots, air gaps exist between the magnets and the slots thereby reducing the magnetic effectiveness of the rotor. During operation of the electric machine, the rotor magnets are subjected to centrifugal forces which force the magnets radially outward and to impact an outer lip of the pole pieces, causing damage to the magnet material.